VSTS deployment fails with “Authorization failed f

Question

I'm deploying an ARM template with VSTS which contains a lock (in my case lock on a Storage Account for a Function App)

{
    "parameters": {
        "name": {
            "type": "string"
        },
        "storageName": {
            "type": "string"
        },
        "location": {
            "type": "string"
        }
    },
    "resources": [
        {
            "apiVersion": "2015-05-01-preview",
            "type": "Microsoft.Storage/storageAccounts",
            "name": "[parameters('storageName')]",
            "location": "[parameters('location')]",
            "properties": {
                "accountType": "Standard_LRS"
            },
            "resources": [
                {
                    "type": "Microsoft.Storage/storageAccounts/providers/locks",
                    "name": "[concat(parameters('storageName'), '/Microsoft.Authorization/', parameters('storageName'))]",
                    "apiVersion": "2015-01-01",
                    "dependsOn": [
                        "[concat('Microsoft.Storage/storageAccounts/', parameters('storageName'))]"
                    ],
                    "properties": {
                        "level": "CannotDelete",
                        "notes": "One or more function apps were linked to this storage account. You can see all the function apps linked to the account under 'files' or 'shares'."
                    }
                }
            ]
        },...

That just works fine when deploying from VS or from command line with my credentials. However when deploying from a VSTS release definition, the deployment fails with:

Resource Microsoft.Resources/deployments 'myFunctionApp' failed with message '{
  "error": {
    "code": "InvalidTemplateDeployment",
    "message": "The template deployment failed with error: 'Authorization failed for template resource 'myFunctionAppStorage/Microsoft.Authorization/myFunctionAppStorage' of type 'Microsoft.Storage/storageAccounts/providers/locks'. The client '***VSTS service principal Id***' with object id '***VSTS service principal Id***' does not have permission to perform action 'Microsoft.Authorization/locks/write' at scope '/subscriptions/*** subscription ***/resourceGroups/*** resource group ***/providers/Microsoft.Storage/storageAccounts/myFunctionAppStorage/providers/Microsoft.Authorization/locks/myFunctionAppStorage'.'."
  }
}

When I remove the Microsoft.Storage/storageAccounts/providers/locks section from the template, the VSTS deployment works. But then the storage account would bear no lock preventing a deletion.

Answer 1

Contributor role - which is assigned when VSTS creates the Service Principal in the AAD connected to the Resource Groups Subscription - is not sufficient for placing the lock. Assign Owner and the lock can be placed with the VSTS deployment process.